Focusing on the polygon places the apex of the solid

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Focusing on the Polygon places the Apex of the Solid Cone of Light produced by the Condenser on the Specimen. 10. Open-up the focused Polygon so it’s opened-up as much as possible but still Visible at the Edges of the Field of View (See Figure 3-1c). Figure 3-1. (a) Image of a stopped-down but Off-Center Field Diaphragm (b) Image ofa stopped-down and Centered Field Diaphragm (c) Image of a Field Diaphragm opened to just fully fill the Field of View (while still being Visible).
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Lab 3 Page 7 11. Center the Polygon with the Silver Condenser Centering Screws on the Condenser. We ʼ re using the Image of the Polygon to (A) Size and then (B) Center the Cone of Light being produced by the Condenser. The two Condenser Centering Screws are opposed by a single Spring. Centering the Polygon is like drawing 45° Line with an Etch-A-Sketch. 12. Adjust the Field Diaphragm until the Polygon just fully fills the Field of View. This will probably be ~14 on the Field Diaphragm Scale. Imagine you ʼ re picking a Flashlight to illuminate the Inside of a Birdhouse. If you use a very large Diameter Flashlight most of the Light is going to be wasted on the Outside of the Birdhouse. If you use a very small Diameter Flashlight all of the Light will enter the Birdhouse but there won ʼ t be enough to illuminate the Interior. You ʼ d want to match the Size of the Flashlight fairly closely to the Size of the Opening of the Birdhouse for maximum Efficiency. Be sure and note the Setting on your Field Diaphragm where the Polygon completely fills the Field of View. On most Microscopes this ʼ ll be somewhere around “14”. 13. Slowly remove the Right Eyepiece by carefully pulling it straight out. Set the Eyepiece down Right-Side-Up and away from the Edge of the Bench. Always remove the Right Eyepiece (without the Eyepiece Reticle). Your Zeiss Microscope is as Air-Tight as a 1968 Volkswagen. So when you pull-out an Eyepiece, you ʼ re creating a Partial Vacuum within the Microscope that would dislodge the Ocular Micrometer in the Left Eyepeice (which is why you should remove the Right Eyepeice). 14. Adjust the Condenser Diaphragm such that 3/4 of the Field of View is filled with Light (i.e. close-down the Condenser Diaphragm by about 1/4). If you ʼ re looking West while skiing at Tahoe, you ʼ ll probably raise your Hand above your Eyes to shield them from Glare. We ʼ re doing the same thing here by closing down the Cone of Light a bit so those Light Rays at the Edges and outside of the Cone of Light (the ones producing “Glare”) are blocked. You centered the Field Diaphragm in Step 11. Now you ʼ re adjusting the Condenser Diaphragm. Don ʼ t worry if this guy isn ʼ t centered. 15. Replace the Right Eyepiece. 16. Use the Mechanical Stage Controls to move the “P” back into Place. If the P is still in focus, you did it! If the P is not in Focus, you screwed-up!
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